Templates: various questions not worth their own thread

[chaley]

Originally Posted by ownedbycats

if select(ids, 'url') then
	if 
		'(Archive of Our Own|Fanfiction.net)' in $publisher 
		&& '(Completed|Abandoned|Oneshot|Incomplete)' in status
	then "metadata.png"

	elif
		!select(ids, 'ao3')
		&& $publisher == 'Archive of Our Own' 
		&& status == 'In-Progress'
		then 'metadata.png' 
	
	elif 
		!select(ids, 'ffnet')
		&& $publisher == 'FanFiction.net'
		&& status == 'In-Progress'
		then "metadata.png" 
	fi 
fi

Would it be able to combine the two bottom elifs into one? Regex (ao3|ffnet) is one way, but is there a way to keep the id/publisher pair separate from each other?

I think you mean something like this:

program:
	if 
		'(Archive of Our Own|Fanfiction.net)' in $publisher 
		&& '(Completed|Abandoned|Oneshot|Incomplete)' in status
	then "metadata.png"

	elif	(!select(ids, 'ao3')
		 && $publisher == 'Archive of Our Own' 
		 && status == 'In-Progress' )
	      ||
		(!select(ids, 'ffnet')
		 && $publisher == 'FanFiction.net'
		 && status == 'In-Progress')
	then
		"metadata.png" 
	fi

EDIT: Another question:

Attachment 191967

Did I somehow accidentally turn it into last_non_empty?

No. But by using a semicolon instead of a comma you turned the two 'if' statements into a single statement sequence, not two parameters. The value of a statement sequence is the last statement in the sequence, in your case the authors if.

It should look like this:

program:
	first_non_empty(
		if $title then 'title' fi, <==== comma here
		if $authors then 'authors' fi
	)

[ownedbycats]

Originally Posted by chaley

I think you mean something like this:

program:
	if 
		'(Archive of Our Own|Fanfiction.net)' in $publisher 
		&& '(Completed|Abandoned|Oneshot|Incomplete)' in status
	then "metadata.png"

	elif	(!select(ids, 'ao3')
		 && $publisher == 'Archive of Our Own' 
		 && status == 'In-Progress' )
	      ||
		(!select(ids, 'ffnet')
		 && $publisher == 'FanFiction.net'
		 && status == 'In-Progress')
	then
		"metadata.png" 
	fi

Thanks Since both of them use in-progress I was able to reduce it a tiny bit more:

elif						
	(status == 'In-Progress' &&
	(!select(ids, 'ao3')  && $publisher == 'Archive of Our Own') 						
	||
	(!select(ids, 'ffnet') && $publisher == 'FanFiction.net')	
	)
then "metadata.png"

[chaley]

Originally Posted by ownedbycats

Thanks Since both of them use in-progress I was able to reduce it a tiny bit more:

elif						
	(status == 'In-Progress' &&
	(!select(ids, 'ao3')  && $publisher == 'Archive of Our Own') 						
	||
	(!select(ids, 'ffnet') && $publisher == 'FanFiction.net')	
	)
then "metadata.png"

You should pay attention to operator precedence and the implied parentheses. The && operator has higher precedence than the || operator, so your statement will evaluate like this:

program:
if
		(	status == 'In-Progress' &&
			(!select(ids, 'ao3')  && $publisher == 'Archive of Our Own') 						
		) 
	||
		(
			(!select(ids, 'ffnet') && $publisher == 'FanFiction.net')	
		)
then "metadata.png"
fi

That isn't what you want because the status == isn't done for the 'ffnet' branch. Instead you want this:

program:
if	status == 'In-Progress' &&
	(
			(!select(ids, 'ao3')  && $publisher == 'Archive of Our Own')

		||
			(!select(ids, 'ffnet') && $publisher == 'FanFiction.net')	
	)
then "metadata.png"
fi

By putting the second two checks in parentheses you ensure that the status == check is done for both of them.

My advice: don't depend on operator precedence unless you really know what you are doing. Instead use parentheses to specify the order of evaluation.

EDIT: I forgot to mention: factoring conditions in ifs is a very good thing for performance and readability. It makes the flow clearer and takes maximum advantage of condition short circuiting. Good that you noticed it.

[ownedbycats]

The downside of nesting ifs is that it's very easy to misplace fis. I've gotten into the habit of adding ## Start/End [something] check comments just so I remember what they belong to.

[chaley]

Originally Posted by ownedbycats

The downside of nesting ifs is that it's very easy to misplace fis. I've gotten into the habit of adding ## Start/End [something] check comments just so I remember what they belong to.

That is one reason that consistent indenting is so important. If done correctly the if and fi will be at the same indent.

One trick you can use to match a fi with its if. Put a left parenthesis in front of the if. The editor will complain about a syntax error. Now put a right parenthesis after the fi that you think matches (but before any semicolon). If the error goes away then they indeed match. If there is still an error then the if and fi don't match.

[ownedbycats]

That will be useful to know

Also, something like this

if 
	variable == 'foo' 
	&& anothervariable
	&& thirdvariable != 'bar' 
then
	'foobar'

makes it easier to comment out specific checks to see how things change.

[ownedbycats]

Does if $#columname== '' work for all undefined columntypes? (excluding the default columns 'title' and 'author')

[chaley]

Originally Posted by ownedbycats

Does if $#columname== '' work for all undefined columntypes? (excluding the default columns 'title' and 'author')

Yes, undefined is rendered as the empty string for all column types. The columns title and author aren't special in this sense, but they are never undefined.

Note that !$#mumble is equivalent to $#mumble=='' but faster.

[ownedbycats]

EDIT: It was a regex error.

[ownedbycats]

Not quite a template question, but did I make a mistake on this saved search? I'm getting VL recursion errors:

NOT formats:(paperbook|overdrive) OR NOT formats:#=1

EDIT: Changing to formats:"~(overdrive|paperbook)" worked. Not exactly sure why.

[ownedbycats]

program: 

   strcat(
		icons_readstatus(),
		icons_fanfic(),
		icons_devicestatus(),
		icons_formats(),
	)

How do I add a colon to this so that the icon strings don't run together? icons_readstatus()':' made an error and 'icons_readstatus():' returned literally that.

[chaley]

Originally Posted by ownedbycats

program: 

   strcat(
		icons_readstatus(),
		icons_fanfic(),
		icons_devicestatus(),
		icons_formats()
	)

How do I add a colon to this so that the icon strings don't run together? icons_readstatus()':' made an error and 'icons_readstatus():' returned literally that.

program: 

   strcat(
		icons_readstatus(), ':', 
		icons_fanfic(), ':',
		icons_devicestatus(), ':',
		icons_formats(),
	)

[ownedbycats]

Silly question:

I have this rule in emblems:

program: 

	first_non_empty(
		icons_cleanup_metadata(),
		icons_cleanup_missingids(),
		icons_cleanup_fanfic(),
		icons_marked(),
		if 'Cleanup' in virtual_libraries() then 'polish.png' fi
	)

Line 7 results in a duplicate pin icon, like this:



So I tried replacing with if is_marked() then '' fi and... wait, that's an empty:



Invis.png doesn't really work quite as expected either:



Is there a better option than first_non_empty? For now, I'm using if is_marked() then 'nope' fi as that won't render anything.

[chaley]

Originally Posted by ownedbycats

Silly question:

I have this rule in emblems:

program: 

	first_non_empty(
		icons_cleanup_metadata(),
		icons_cleanup_missingids(),
		icons_cleanup_fanfic(),
		icons_marked(),
		if 'Cleanup' in virtual_libraries() then 'polish.png' fi
	)

[...]
Is there a better option than first_non_empty? For now, I'm using if is_marked() then 'nope' fi as that won't render anything.

You can use a series of ifs like this:

program: 
	if 	v = icons_cleanup_metadata() then v
	elif	v = icons_cleanup_missingids() then v
	elif	v = icons_cleanup_fanfic() then v
	elif	v = icons_marked() then v
	elif   'Cleanup' in virtual_libraries() then 'polish.png'
	fi

It stops at the first condition that is true, returning whatever v is even if it is empty.

With your change the icons_marked line would become

	elif	is_marked() then ''

The condition is true so it returns the empty string.

The two 'tricks' are:

• The value of an if statement is the value of a then or else block. That is why it has the value of the first evaluated then block.
• Use the embedded assignment so you don't need to call the function (stored template) twice or can return whatever you want as you do in the last elif.

[chaley]

BTW: you can also do it using a series of ifs with return statements as long as you don't do any processing after the last one.

program: 
	if v = icons_cleanup_metadata() then return v fi;
	if v = icons_cleanup_missingids() then return v fi;
	if v = icons_cleanup_fanfic() then return v fi;
	if is_marked() then return '' fi;
	if 'Cleanup' in virtual_libraries() then return 'polish.png' fi